Search

DNA collections are a valuable type of Natural Science collection, enabling the validation of past research, serving as a source for new genomic studies and supporting ex situ conservation. The DiSSCo Flanders DNA collection working group, aiming to advance and "unlock" their DNA collections, identified the need for: 1) actively sharing best practices regarding the management of DNA collections; and 2) providing guidance on how to bring theory into practice. By combining best practice examples from within the working group with available literature and brainstorming ideas, the working group co-created two outputs, referred to as: the "Challenges" and the "Key". The Challenges are a list of obstacles to DNA collection management, which shape the structure of the linked Key and can also be used to spark discussion amongst stakeholders. The Key is a tool that guides users through the maturation process of their DNA collection in a standardised way. It stimulates holistic growth, breaks down the needed work into manageable steps and helps to decide priorities during the process. Furthermore, the Key facilitates communication with both internal stakeholders and external DNA collection managers. The Key distinguishes itself from other self-assessment tools in several ways: it includes (re)investigation of the collection’s purpose and context; it is specialised for DNA collections; it delivers concrete goals linked to relevant information and shared experience; and it is inclusive, targeting all Natural Science DNA collections, regardless of their context or size.

Abstract Background Persistent human papillomavirus (HPV) infection is considered the primary etiological factor for invasive cervical cancer. Understanding the epidemiology of circulating potential high-risk (HR) and HR HPV strains is essential in updating epidemiological knowledge and recommendations on genotype-specific vaccination development. This study determined the prevalence and factors associated with Potential HR/HR HPV among women attending selected reproductive health clinics in Lake Victoria Basin. Methods A cross-sectional facility-based survey made up of 434 women aged 16–68 years was carried out in two selected facilities. Structured questionnaires were administered to collect participant clinical and social characteristics. Cervical specimens were collected and HPV genotyping was carried out using RIATOL HPV genotyping qPCR assay. Descriptive statistics followed by logistic binary regression was done using R version 4.3.2. Results The overall prevalence of potential HR/HR HPV among women attending the selected reproductive health clinics was reported at 36.5% (158/434). Specifically, in the rural setting, Gobei Health Center, the prevalence was 41.4% (41/99) while in the urban setting-JOOTRH, it was 34.6% (117/335). The most prevalent potential HR/HR HPV are 52, 67, 16, 31, 39, 45, and 31 among women. Age was the main factor associated with HPV infection with women between the age of 30–39 having the highest risk (AOR = 0.3, CI:0.2–0.7, p

The implementation of a laboratory exercise in an undergraduate chemistry course, where students perform a comparison of three different synthetic methods toward [Cu(Cl)(IPr)]-complexes (IPr = N,N'-bis(2,6-diisopropylphenyl)imidazol-2-ylidene), is described. The students are introduced to the continuous improvement of reactions in terms of green chemistry and are provided a taste of mechanochemistry as a synthetic methodology. The direct comparison of three methods leading to the copper complexes provides an opportunity to teach green chemistry metrics including atom economy, environmental factor, mass intensity, reaction mass efficiency, and optimum efficiency, as well as Green Star; and challenges them to question the use of solvents in chemical syntheses.

ABSTRACT Clinically validated human papillomavirus (HPV) assays are crucial in cervical cancer screening. In this study, we evaluated the Allplex HPV HR Detection assay (Seegene, SouthKorea) for its clinical accuracy and reproducibility according to the international criteria, using the RealTime High Risk HPV m2000 assay (Abbott, USA) as standard comparator. The Allplex HPV HR assay exhibits significant non-inferior sensitivity to detect cervical intraepithelial neoplasia grade (CIN) 2 or worse (CIN2+) with a ratio of 1.00 (95% CI: 0.97–1.03, P = 0.006), insignificant non-inferior sensitivity to detect CIN3+ with a ratio of 1.00 (95% CI: 0.88–1.13, P = 0.098), and non-inferior specificity to exclude CIN2+ with a ratio of 0.99 (95% CI: 0.99–1.00, P < 0.001) compared to the standard comparator. In addition, the assay shows an excellent reproducibility within the same laboratory [96.5% (95% CI: 94.6–97.9) with a kappa value of 0.91 (95% CI: 0.87–0.95)] and between laboratories [96.7% (95% CI: 94.8–98.0) with a kappa value of 0.91 (95% CI: 0.87–0.95)] for overall high-risk HPV positivity as well as for each individual HPV type. Pooling our study data with those of another independent study supports the consistency of our findings. We conclude that both the clinical accuracy to detect cervical precancer and the reproducibility of Allplex HPV HR Detection assay fulfill the international validation criteria of use in cervical cancer screening.IMPORTANCEThe clinical validation of human papillomavirus (HPV) assays in accordance with well-established international guidelines is crucial to ensure that only validated assays are used in the context of screening (Meijer et al., Int J Cancer, 2009). The guidelines, developed by an international consortium, require that a novel HPV assay has non-inferior accuracy against a standard comparator test for the detection of cervical intraepithelial neoplasia grade (CIN) 2 or worse (CIN2+). Additionally, a new HPV assay should meet specific criteria for both intra- and inter-laboratory reproducibility to ensure the assay consistently exhibits technical precision and robust performance. Pooling our study data with those of another independent study supports the consistency of our findings. In conclusion, both the clinical accuracy to detect cervical precancer and the reproducibility of Allplex HPV HR Detection assay fulfill the international validation criteria of use in cervical cancer screening.

Abstract Background Despite the increasing number of epigenomic studies in plants, little is known about the forces that shape the methylome in long-lived woody perennials. The Lombardy poplar offers an ideal opportunity to investigate the impact of the individual environmental history of trees on the methylome. Results We present the results of three interconnected experiments on Lombardy poplar. In the first experiment, we investigated methylome variability during a growing season and across vegetatively reproduced generations. We found that ramets collected over Europe and raised in common conditions have stable methylomes in symmetrical CG-contexts. In contrast, seasonal dynamics occurred in methylation patterns in CHH context. In the second experiment, we investigated whether methylome patterns of plants grown in a non-parental environment correlate with the parental climate. We did not observe a biological relevant pattern that significantly correlates with the parental climate. Finally, we investigated whether the parental environment has persistent carry-over effects on the vegetative offspring’s phenotype. We combined new bud set observations of three consecutive growing seasons with former published bud set data. Using a linear mixed effects analysis, we found a statistically significant but weak short-term, parental carry-over effect on the timing of bud set. However, this effect was negligible compared to the direct effects of the offspring environment. Conclusions Genome-wide cytosine methylation patterns in symmetrical CG-context are stable in Lombardy poplar and appear to be mainly the result of random processes. In this widespread poplar clone, methylation patterns in CG-context can be used as biomarkers to infer a common ancestor and thus to investigate the recent environmental history of a specific Lombardy poplar. The Lombardy poplar shows high phenotypic plasticity in a novel environment which enabled this clonal tree to adapt and survive all over the temperate regions of the world.

Abstract Background Self-collection of cervical samples to detect high-risk human papillomavirus (hr-HPV) is a trending topic in primary cervical cancer screening. This study evaluates the applicability of a self-sampling device to routine molecular procedures for hr-HPV detection. Methods In a primary health care facility in Kinshasa, Congo, 187 self-collected samples (Evalyn Brush) were gathered and sent to Ghent University Hospital (UZ Ghent) and Algemeen Medisch Labo (AML) in Belgium where routine tests for hr-HPV were applied (Abbott RealTime hr-HPV and qPCR (E6/E7), respectively). Sample type effect was evaluated by comparing the internal control (IC) between the self-collected samples and routine, clinician-taken samples randomly selected from the UZ Ghent archive. Results In UZ Ghent an error was encountered in 9.1% (17/187) of self-collected samples due to a lack of IC signal. The hr-HPV prevalence in the remaining 170 samples was 18,8%. Comparing IC results between the self-collected and clinician-collected groups, a significant difference (p

Abstract Cutaneous warts are benign skin lesions caused by the human papillomavirus (HPV). Even though they are considered benign, they can have a considerable impact on the quality of life and cause serious illness in certain immunocompromised populations. Studies have shown that the efficacy of wart treatment is dependent on the causative HPV type. Therefore, in this article, we aim to determine the HPV genotype-specific prevalence in cutaneous warts of a Flemish population as part of the Omnivirol-Salycilic acid randomized controlled trial. Swab samples of cutaneous warts (n = 269) were collected during enrollment. The DNA extraction was performed on the automated NucliSENS® easyMAG® system (bioMérieux). The samples were analyzed with two separate in-house PCR assays capable of detecting the most prevalent cutaneous HPV types (i.e. wart-associated HPV qPCR) as well as the most relevant mucosal types (i.e. RIATOL qPCR assay). In total, the type-specific prevalence of 30 distinct HPV genotypes was determined. The beta-globin gene was used as a cellularity control and for viral load quantification. Data concerning wart persistence, previous treatment, wart type, and other relevant wart and patient characteristics was collected through a baseline questionnaire. The study population consisted mostly of persistent warts considering that 98% (n = 263) of the sampled skin lesions were older than six months and 92% (n = 247) had undergone previous treatment. The most prominent wart type was the mosaic verruca plantaris (42%, n = 113). The most prevalent HPV types were cutaneous HPV types 27 (73%, n = 195), 57 (63%, n = 169), and 2 (42%, n = 113). Only 2% (n = 6) of the lesions was HPV negative. The highest median viral loads were observed with HPV27 and 57 (i.e. 6.29E+04 and 7.47E+01 viral copies per cell respectively). The multivariate analysis found significant associations between wart persistence and certain wart types, the number of warts, and HPV genotypes. Based on these findings, persistent warts are more likely to: (1) be verruca vulgaris, verruca plantaris simple or mosaic, (2) to manifest as multiple warts, (3) and to be negative for HPV type 2 or 4. These characteristics can be useful in the clinical setting for future risk stratification when considering treatment triage and management. Trial registration: NCT05862441, 17/05/2023 (retrospectively registered).

Abstract One of the challenges faced by current CRISPR/Cas9 editing strategies is the difficulty in rapidly selecting clonal populations of biallelically edited cells. Here we present Surface engiNeered fluorEscence Assisted Kit with Protein Epitope Enhanced Capture (SNEAK PEEC), a platform that combines human genome editing with cell-surface display, which enables the direct identification of biallelically edited clones with minimal screening.

In his posthumously published work on education, Niklas Luhmann (1927-1998) described his approach to the sociological observation of the educational system as a formal one. Only by refraining from more substantial definitions, based on what teachers hope to convey, he claimed, can education be understood in all its historical and geographical varieties. By rereading his oeuvre as a socio-historical account of modern school education's morphogenesis, I inspect this so-called formal approach more closely and show how it brings together different understandings of its central notion, form. The underlying theoretical movements of Luhmann's formal approach, composed of indication and delimitation, of generalisation and re-specification, provide useful hints for the study of those forms of education which today increasingly emerge outside of its formal institutions.

In an effort to address the relationship between globalisation, education and Niklas Luhmann's branch of systems theory, we present his essay, published here for the first time in English translation, 'Education: Forming the life course', next to the nine contributions that compose this special issue and build on this and his other writings to take up the theme of education in world society. To conclude, we underline that systems theory's emphasis on functional differentiation helps to address two lacunae in the today prevailing sociological practice. By positing the development of self-referential domains as modernity's central mode of differentiation, it provides sociology with a comprehensive theory of world society. By the same token, it also allows one to observe education as a global affair with, so to speak, a life of its own. [For "Education: Forming the Life Course," see EJ1314934.]

The digestive tract constitutes an important interface between an animal’s internal and external environment. In insects, available gut transcriptome studies are mostly exploratory or look at changes upon infection or upon exposure to xenobiotics, mainly performed in species belonging to holometabolan orders, such as Diptera, Lepidoptera or Coleoptera. By contrast, studies focusing on gene expression changes after food uptake and during digestion are underrepresented. We have therefore compared the gene expression profiles in the midgut of the desert locust, Schistocerca gregaria, between three different time points after feeding, i.e., 24 h (no active digestion), 10 min (the initial stage of feeding), and 2 h (active food digestion). The observed gene expression profiles were consistent with the polyphagous herbivorous lifestyle of this hemimetabolan (orthopteran) species. Our study reveals the upregulation of 576 genes 2 h post-feeding. These are mostly predicted to be associated with digestive physiology, such as genes encoding putative digestive enzymes or nutrient transporters, as well as genes putatively involved in immunity or in xenobiotic metabolism. The 10 min time point represented an intermediate condition, suggesting that the S. gregaria midgut can react rapidly at the transcriptional level to the presence of food. Additionally, our study demonstrated the critical importance of two transcripts that exhibited a significant upregulation 2 h post-feeding: the vacuolar-type H(+)-ATPase and the sterol transporter Niemann-Pick 1b protein, which upon RNAi-induced knockdown resulted in a marked increase in mortality. Their vital role and accessibility via the midgut lumen may make the encoded proteins promising insecticidal target candidates, considering that the desert locust is infamous for its huge migrating swarms that can devastate the agricultural production in large areas of Northern Africa, the Middle East, and South Asia. In conclusion, the transcriptome datasets presented here will provide a useful and promising resource for studying the midgut physiology of S. gregaria, a socio-economically important pest species.

Background: In previous years, several cutaneous disorders have been associated with human papillomavirus (HPV); however, the exact role of HPV remains largely unknown. The lack of optimization and standardization of the pre-analytical phase forms a major obstacle. The aim of this study was to develop an accurate/patient-friendly sampling method for skin disorders, with cutaneous warts as a case study. Methods: Various sample processing techniques, pre-treatment protocols and DNA extraction methods were evaluated. Several sampling methods were examined, that is, skin scrapings, swabs and a tape-based method. Quantification of DNA yield was achieved by beta-globin real-time polymerase chain reaction (qPCR), and a wart-associated HPV genotyping qPCR was used to determine the HPV prevalence. Results: All samples tested positive for beta-globin. Skin scrapings had significantly higher yield than both swab and tape-based methods ( p 0.05). No significant difference in DNA yield was found between cotton and flocked swabs ( p > 0.05). All swabs were HPV positive, and although there were some discrepancies in HPV prevalence between both swabs, an overall good strength of agreement was found [κ = 0.77, 95% CI (0.71–0.83)]. Conclusion: Although skin scrapings produced the highest DNA yield, patient discomfort was an important limitation of this method. Considering that in combination with our optimized DNA extraction procedure, all samples gave valid results with the less invasive swab methods preferred. Standardization of the pre-analytical phase is the first step in establishing a link between HPV and specific skin disorders and may have significant downstream diagnostic as well as therapeutic implications.

Pausing of RNA polymerase (RNAP) and transcription is regulated by the NusA and NusG transcription factors in bacteria. Here the authors provide structural evidence for how they interact with RNAP to carry out their pausing roles and also reveal functions for NusA and NusG in transcription termination.

Across the globe, education has recently been through a major semantic shift, where new notions such as 'learning', 'competences', 'projects' came to replace or complement an older, more established, educational vocabulary. The political approach to education has also evolved, as many authors have underlined, from established national forms of governing to global, transnational forms of governance. These evolutions, often abbreviated to shifts 'from teaching to learning' and 'from governing to governance' have resonated globally and attracted the attention of researchers. Most sociological accounts of such evolutions attribute them to the development and primacy of a preponderant logic, generally politics/power, culture or the economy. Niklas Luhmann's systems theory, on which we draw in this article, suggests to start from a different, opposite, premise: not the predominance but instead the lack of any predominant logic characterizes modernity. The functional differentiation of modern society into a multiplicity of--specific yet universal--systems should therefore be the pivotal point that helps make sense of these transformations. We argue that the very coexistence of such systems, their simultaneous and therefore uncoordinated existences, increases the complexity of the social world tremendously and leaves them with an uncertain future. The so-called turns to governance and to learning, we argue, should be understood, respectively, as political and educational attempts to deal with this loss of direction.

The current inclination, at the European level, to fund education in the form of projects radicalises the modern orientation towards the present as the attempt to bind a yet indeterminate future. This article proposes a close re-reading of Niklas Luhmann's sociological oeuvre in order to problematise the place of the present in modern education. In an effort to sketch out the need for a new educational ecology, it then draws attention to how transnational projects articulate their educational meaning.

In 2014 the European Commission introduced a reform of its previous funding efforts in the realm of education, which grouped them together under a single banner, baptised 'Erasmus+'. The programme offers financial support for projects of transnational networks that are capable of gathering, even if only temporarily, a plurality of organisations, educational and non-educational alike, around a once-only objective, that is not expected to be repeated. Thus far sociologists and anthropologists have dealt with this topic mainly through the lens of individual mobility and identity. While such a conceptual prism allows for important questions on the construction of meaning and changes in social status, it falls short both empirically and theoretically when it comes to understanding how this reformed action programme constitutes a distinct formalisation of education, deviating from the morphogenesis of the national school system. Drawing on the theoretical framework of Niklas Luhmann, this article argues for understanding such Europeanisation of education as a means for growth by internal disjunction. That is: as an internal differentiation of the global education system, which surpasses the limits the former developed in reference to the nation-state, thus resettling and dramatically expanding the limits of what counts as meaningful education.

Abstract Background To set up successful conservation measures, detailed knowledge on the dispersal and colonization capacities of the focal species and connectivity between populations is of high relevance. We developed species-specific nuclear microsatellite molecular markers for the grayling (Hipparchia semele), a butterfly endemic to Europe and of growing conservation concern in North-West Europe, and report on its population genetics, in a fragmented, anthropogenic landscape in Belgium. Our study included samples from 23 different locations nested in two regions and additional historical samples from two locations. We assessed contemporary, long-distance dispersal based on genetic assignment tests and investigated the effect of habitat loss and fragmentation on the population genetic structure and genetic variation using data of nine microsatellite loci. Results Detected dispersal events covered remarkably long distances, which were up to ten times larger than previously reported colonisation distances, with the longest movement recorded in this study even exceeding 100 km. However, observed frequencies of long-distance dispersal were low. Our results point to the consequences of the strong population decline of the last decades, with evidence of inbreeding for several of the recently sampled populations and low estimates of effective population sizes (Ne) (ranging from 20 to 54 individuals). Conclusions Our study shows low frequencies of long-distance dispersal, which is unable to prevent inbreeding in most of the local populations. We discuss the significance for species conservation including future translocation events and discuss appropriate conservation strategies to maintain viable grayling (meta) populations in highly fragmented, anthropogenic landscapes.

ABSTRACT The VALHUDES framework (NCT03064087) was established to evaluate the clinical accuracy of HPV testing on self-samples compared with HPV testing on matched clinician-taken cervical samples. Women referred to colposcopy due to previous cervical abnormalities were recruited at five Belgian colposcopy centers. A total of 486 pairs of matched cervical samples and vaginal self-samples were included in the analysis (228 collected with Evalyn Brush and 258 with Qvintip). The dry vaginal brushes were transferred into 20 mL ThinPrep PreservCyt solution. All specimens were tested with the Abbott RealTime High Risk HPV assay (Abbott RT). Testing on vaginal and cervical specimens was considered the index and comparator tests, respectively, and colposcopy and histology as the reference standard. The clinical sensitivity for CIN2+ of Abbott RT (cutoff ≤32 cycle number [CN]) on vaginal self-samples (Evalyn Brush and Qvintip combined) was 8% lower than on the cervical clinician-collected samples (ratio = 0.92 [95% CI, 0.87 to 0.98]), while the specificity was similar (ratio = 1.04 [95% CI, 0.97 to 1.12]). Sensitivity (ratio = 0.95 [95% CI, 0.89 to 1.02]) and specificity (ratio = 1.11 [95% CI, 0.995 to 1.23]) on Evalyn Brush samples was similar to cervical, while on Qvintip samples, the sensitivity was 12% lower than cervical samples (ratio = 0.88 [95% CI, 0.78 to 0.998]) with similar specificity (0.99 [95% CI, 0.90 to 1.10]). Exploratory cutoff optimization (cutoff ≤35 CN) resulted in an improvement of the relative sensitivity (self-sampling versus clinician sampling: ratio = 0.96 [95% CI, 0.91 to 1.02]) but yielded a loss in relative specificity (ratio = 0.92 [0.85 to 1.00]). The clinical accuracy of Abbott RT differed from the self-sampling device. However, after cutoff optimization, the sensitivity on self-samples taken with either of two vaginal brushes became similar to clinician-collected samples. IMPORTANCE Self-samples are becoming a crucial part of HPV-based cervical cancer screening programs to reach nonattendee women and increase screening coverage. Therefore, the VALHUDES framework was established to validate and evaluate HPV tests and devices on self-samples. Here, in the present manuscript, we evaluated the accuracy of the RealTime High Risk HPV assay (Abbott RT) on two different vaginal devices to detect cervical intraepithelial neoplasia grade two or higher (CIN2+). The study results demonstrated that the Abbott RT assay is similarly accurate on vaginal self-samples as on matched clinician-taken cervical samples after adjusting cutoff values. Moreover, we observed that some vaginal devices perform better than others in CIN2+ detection. We also underline the necessity of standardization and validation of general workflow and sample handling procedures for vaginal self-samples.

RNA(i) interference is a gene silencing mechanism triggered by double-stranded (ds)RNA, which promises to contribute to species-specific insect pest control strategies. The first step toward the application of RNAi as an insecticide is to enable efficient gene silencing upon dsRNA oral delivery. The desert locust, Schistocerca gregaria is a devastating agricultural pest. While this species is responsive to dsRNA delivered by intra-hemocoelic injection, it is refractory to orally delivered dsRNA. In this study, we evaluated the capacity of five cell-penetrating peptides (CPPs) to bind long dsRNA and protect it from the locust midgut environment. We then selected the CPP EB1 for further in vivo studies. EB1:dsRNA complexes failed to induce RNAi by feeding. Interestingly, we observed that intra-hemocoelic injection of small-interfering (si)RNAs does not result in a silencing response, but that this response can be obtained by injecting EB1:siRNA complexes. EB1 also protected siRNAs from midgut degradation activity. However, EB1:siRNA complexes failed as well in triggering RNAi when fed. Our findings highlight the complexity of the dsRNA/siRNA-triggered RNAi in this species and emphasize the multifactorial nature of the RNAi response in insects. Our study also stresses the importance of in vivo studies when it comes to dsRNA/siRNA delivery systems.

Abstract Background Interventions to reach women who do not participate regularly in screening may reduce the risk of cervical cancer. Self-collection of a vaginal specimen has been shown to increase participation. The relative clinical accuracy of human papillomavirus (HPV) testing on first-void urine (with Colli-Pee) and on vaginal self-samples versus on cervical clinician-collected samples is being investigated in the VALHUDES trial. The current study assesses attitudes and experiences regarding self-sampling among women enrolled in VALHUDES. Methods Questionnaires from 515 women (age 25–64 years [N = 498]; 95%) declared that instructions for self-collection were clear, that collection was easy, and that they were confident about having performed the procedure correctly, for both urine and vaginal collection. However, a proportion of women found self-sampling unpleasant (9.5% [49/515] for urine collection; 18.6% [96/515] and 15.5% [80/515] for vaginal sampling with cotton swabs or plastic brushes, respectively). For their next screening round, 57% would prefer self-sampling whereas 41% opted for collection by a clinician. Among women preferring self-sampling, 53% would choose for urine collection, 38% for vaginal self-collection and 9% had no preference. Age did not modify preferences. Conclusion We conclude that both urine and vaginal self-sampling are well accepted by women, with a preference for urine sampling. Although the large majority of women are confident in their ability to perform self-sampling, four to five over ten women preferred specimen collection by a clinician. Trial registration The study VALHUDES was registered in ClinicalTrials.gov (identifier: NCT03064087 ).

Type 2 DNA topoisomerases (Top2) regulates DNA topology during DNA replication, transcription, and chromosome segregation. Here the authors describe a complete structure of the catalytic core of the human Topo IIα bound to DNA and etoposide, providing insight into the regulation of Topo IIα activities and how opening of the DNA-gate is spatially connected to the ATPase domain.

Insect cell expression systems are increasingly being used in the medical industry to develop vaccines against diseases such as COVID-19. However, viral infections are common in these systems, making it necessary to thoroughly characterize the viruses present. One such virus is Bombyx mori latent virus (BmLV), which is known to be specific to Bombyx mori and to have low pathogenicity. However, there has been little research on the tropism and virulence of BmLV. In this study, we examined the genomic diversity of BmLV and identified a variant that persistently infects Trichoplusia ni-derived High Five cells. We also assessed the pathogenicity of this variant and its effects on host responses using both in vivo and in vitro systems. Our results showed that this BmLV variant causes acute infections with strong cytopathic effects in both systems. Furthermore, we characterized the RNAi-based immune response in the T. ni cell line and in Helicoverpa armigera animals by assessing the regulation of RNAi-related genes and profiling the generated viral small RNAs. Overall, our findings shed light on the prevalence and infectious properties of BmLV. We also discuss the potential impact of virus genomic diversity on experimental outcomes, which can help interpret past and future research results.

During the last ten years, developments in cryo–electron microscopy have transformed our understanding of eukaryotic ribosome assembly. As a result, the field has advanced from a list of the vast array of ribosome assembly factors toward an emerging molecular movie in which individual frames are represented by structures of stable ribosome assembly intermediates with complementary biochemical and genetic data. In this review, we discuss the mechanisms driving the assembly of yeast and human small and large ribosomal subunits. A particular emphasis is placed on the most recent findings that illustrate key concepts of ribosome assembly, such as folding of preribosomal RNA, the enforced chronology of assembly, enzyme-mediated irreversible transitions, and proofreading of preribosomal particles. [ABSTRACT FROM AUTHOR]